The present invention relates generally to the field of drawer units and more particularly to fully extendible drawer units and couplings therefor.
Fully extendible chests of drawers, abbreviated extendible chests of drawers, are known in many embodiments and, if there is to be full extension with over-extension, i.e. the drawer can be pulled completely out of the carcass, they have respectively three rails, namely a carcass rail, a drawer rail and in between an intermediate rail relatively movable with respect to both rails. In the simplest configuration the three rails are mutually connected to one another via rollers and the intermediate rail is pulled along when the drawer is pulled out. To ensure that the intermediate rail is pulled out evenly, various measures are known by which said intermediate rail is carried along, while the speed at which it is pulled out is reduced in respect of the drawer.
From German patent specification 674548 a guide device for a chest of drawers is known, in which the intermediate rails run on rollers comprising two steps with different diameter. By choosing an unequal diameter ratio of 2:1, for example 8:4, it is achieved that the intermediate rail remains slightly behind and when the drawer is fully pulled out there is good, even support.
To enable even carrying of the two intermediate rails it is proposed in CH-AS 677593 to provide the roller on the intermediate rail with a set of teeth designated to engage in a tooth rod on the carcass rail.
DE-A1 41 21 070 proposes, instead of a set of teeth, connecting the rails by means of a belt which runs via a differential roller and thus allows the speed gradient of the three rails relative to one another to be pre-set.
Because the intermediate rails are pulled out substantially evenly with the drawer, all these known embodiments enable good, even, smooth support of the latter. They are, however, characterized by a complicated construction and are consequently expensive to produce.
An object of the present invention is to create a fully extendible drawer unit which has a simple, cheaply produced construction and allows the drawer to be pulled out and pushed in gentle, without jolting and with ease of movement. A further object of the invention is to create a coupling which enables defined carrying of the intermediate rail.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become more apparent to those skilled in the art upon examination of the following, or may be learned from practice of the invention.
Mounting the differential roller on the front edge of the carcass rail effects constantly non-positive carrying of the intermediate rail right from the start of the pulling out movement of the drawer from the carcass. Once the rear end of the drawer, and therefore of the drawer rail, has passed the differential roller, a coupling on the intermediate rail acts on a carrier on the drawer rail and effects that the two intermediate rails synchronously with the drawer are carried further outwards, thereby guaranteeing constant, problem-free, even support and quiet running of the drawer.
The Invention is explained in more detail with the aid of an illustrated embodiment.
FIG. 1 shows a side view of the carcass, intermediate and drawer rails inside one another.
FIG. 2 shows a side view of the rear end of the drawer rail.
FIG. 3 shows a cross-section through the drawer rail along line Exe2x80x94E in FIG. 2.
FIG. 4 shows a side view of the intermediate rail.
FIG. 5 shows a cross-section through the intermediate rail along line Bxe2x80x94B in FIG. 4.
FIG. 6 shows a cross-section through the intermediate rail along line Cxe2x80x94C in FIG. 4.
FIG. 7 shows a side view of the carcass rail.
FIG. 8 shows a cross-section through the carcass rail along the line Dxe2x80x94D in FIG. 7
FIG. 9 shows a side, view of the rear end of the drawer rail and the intermediate rail placed therein and also the differential roller under the intermediate rail.
FIG. 10 shows a side view of the rear end of the drawer rail and the intermediate rail placed therein and the coupling lifted from the differential roller.
FIG. 11 shows a cross-section along line Axe2x80x94A in FIG. 10 through the three rails.
FIG. 12 shows a side view of the rear end of the drawer rail and the intermediate rail placed therein and also the differential roller on the carcass rail.
FIG. 13 shows a side view of the lever according to a further configuration of the invention before contact with the differential roller.
FIG. 14 shows a side view of the lever in FIG. 13 lifted by the differential roller.
FIG. 15 shows a side view of the three rails with a coupling lever which can be latched in from below.
FIG. 16 shows an enlarged representation of a cross-section, with the lever before latching in.
FIG. 17 shows an enlarged representation of a cross-section with the lever after latching in.
FIG. 18 shows a longitudinal section through the lever and the intermediate rail along line XVIxe2x80x94XVI in FIG. 16.
FIG. 19 shows a cross-section along line XVIIxe2x80x94XVII in FIG. 17.